The salad kits, which contain fully cooked chicken, were shipped nationwide to the warehouse store for sale in its in-store cafes, the USDA said. They were manufactured by APPA Fine Foods of Corona (Riverside County).

The kits were produced on July 4, July 11, July 14, July 18, July 21, July 25, Aug. 1 and Aug. 8, 2014. Box labels bear the establishment number P-21030 inside the USDA mark of inspection.

Michigan health officials confirmed two instances of listeria contamination in products purchased at the chain warehouse's locations, the USDA said. Tests found contamination in only the chicken.

Food safety officials have received no reports of anyone getting sick from eating the salads. Eating food contaminated with the listeria bacterium can cause listeriosis, a serious infection that mainly affects older adults, people with weakened immune systems and pregnant women and newborns.